This invention relates to the simultaneous manufacture of multiple layer semiconductor devices including epitaxial growth of successive layers and and, more particularly, to the growth of mercury-cadmium-telluride detectors of infrared radiation.
Infrared detectors are frequently used for the sensing of infrared radiation. Arrays of such detectors are employed with electronic circuitry for developing images of sources of infrared radiation. Such detectors may be constructed of suitably doped layers of silicon as well as composite structures of cadmium telluride and HgCdTe plus other layers such as metallization and oxide passivation layers.
In view of the large demand for such devices, and in view of the desirability of maintaining uniform optical and electrical characteristics among the devices to be constructed, it is important to have manufacturing aids which facilitate the manufacture of the devices while maintaining quality control in the manufacturing process.
One such manufacturing aid, commonly known as a slider is described in U.S. Pat. No. 4,317,689 issued in the name of Bowers et al on Mar. 2, 1982. Therein, a sliding element having wells for the containment of liquified semiconductor material passes along a base having a recess for holding a substrate wafer upon which successive layers of semiconductor material are grown by liquid-phase epitaxy. The composite structure serves as a graphite furnace boat which holds the semiconductor materials within a furnace, such as a quartz tube surrounded by an electric heating coil.
Devices such as that disclosed in the foregoing patent are advantageous in the construction of semiconductor devices such as HgCdTe infrared detectors. However, a problem is found in that current manufacturing technology requires still further capabilities not provided by the foregoing slider structures. Such capabilities include provision for in-situ substrate etch, provision for successive growths of three or more epitaxial films from totally isolated melts, provision for buffer layer deposition, provision for interlayer in-situ anneals, provision for in-situ melt saturation with CdTe, ability to decant melt oxides, ability to grow layers on multiple (for example, eight or more) wafers simultaneously, and the provision of growth from a totally confined melt.